Indicators, absorption maxima temperature effect

The Effect of Adsorbed Molecules on the Spectrum of the Cu Cations in Zeolites. Figure 5 shows the change in the spectrum corresponding to the transitions between d-electron levels of Cu during dehydration of the zeolite. The spectrum of completely hydrated zeolite revealed a broad absorption band with a maximum at 12,100 cm" Thermal treatment of the zeolite at 100 °C resulted in the appearance of a new absorption band at approximately 15,500 cm" After vacuum treatment at high temperatures, there appeared in the spectrum an absorption band at 11,200 cm" The position of the absorption band due to Cu " in the spectrum of completely hydrated zeolite is close to that of the [Cu(H20)e] complex (12,600 cm" ) (2). This indicates that Cu " enters the hydrated zeolite structure as an octahedral hexaquo-complex. The same conclusion has been reached by other investigators 4, 18, 20) on the basis of e.s.r. spectroscopic measurements of the Cu " cations in completely hydrated zeolites. 

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